TRENTON, N.J. -- Subpoenas have been delivered to four top executives at the Port Authority of New York and New Jersey as part of an ongoing wasteful spending probe by New Jersey Democrats.

The Associated Press has learned that the subpoenas were delivered Thursday morning.

Assemblyman John Wisniewski said top Port officials failed to respond to repeated requests for information on toll increases, political hiring and a canceled multibillion-dollar rail-tunnel.

"We gave the Port Authority numerous chances to cooperate, and time and time again it failed to adequately do so," Wisniewski said. "The Port Authority is an out-of-control agency that has forgotten it serves the public."

Wisniewski, who chairs the Assembly Transportation Committee, was granted subpoena power by fellow Democrats in April to pursue allegations of waste and mismanagement at the bistate agency.

The Port Authority did not immediately provide comment when contacted Thursday.

Republicans have called the so-called information requests a political witch hunt by the head of the state Democratic Party. Wisniewski is said to be interested in seeking the Democratic nomination to run for governor next year.

A 2011 audit by the New York Comptroller found that the Port had wasted nearly a half-billion dollars in overtime over the previous five years.

An independent accounting of agency finances demanded by Govs. Chris Christie of New Jersey and Andrew Cuomo of New York found the agency "challenged" and "dysfunctional." A subsequent report released in September said the agency has made significant reforms, though more work was needed. The second report also said toll increases were crucial if the Port Authority is to fund improvements to its bridges, tunnels and other facilities.

Tolls on the George Washington Bridge and other spans between New York and New Jersey increased by as much as $4 for E-Z Pass users last year, with another $2 increase scheduled for 2014. At the time, the Port Authority estimated the increases would bring in an additional $720 million in annual revenue.

The Record of Woodland Park reported in January that Christie had made at least 50 job referrals to the Port Authority as of his first 15 or so months in office, which would put him ahead of any other governor, Democrat or Republican, on either side of the Hudson River. In a follow-up story, Christie told the Record, "I make no apologies about trying to put some people in place who are going to understand what the view of this administration is and execute ... in a way that's consistent with my policies."